How to trim each string in an array?

Question

I am looking for how to trim each string in an array, in Craft 3.

I would like to check if a string is in an array of strings. The array is from a form submission, a checkbox group.

For example, there are two checkboxes and both of them are checked.

{% set array_checked_values = submission|split(',') %}

A: {{ array_checked_values[0] == "Value A" }}
B: {{ array_checked_values[1] == "Value B" }}

Although I do not know why, only A returns true, but B is false.

However, it returns true.

B': {{ array_checked_values[1]|trim == "Value B" }}

So, I need to trim each string in the array, but I do not know how to do that. None of these three method work.

{% set array_checked_values = submission|split(',')|trim %}

{% set array_checked_values = array_checked_values|trim %}

{% for val in array_checked_values %}
    {% set val = val|trim %}
{% endfor %}

Answer 1

The other way is you can use array map for this.

{% set array_checked_values = submission|split(',')|map(c => c|trim) %}

Answer 2

I have resolved it by myself. Although it will be an roundabout way, create another array. When each of the values is migrated, the string can be trimmed.

{% set array_checked_values = submission[field.handle]|split(',') %}
{% set array_checked_values_2 = [] %}

{% for val in array_checked_values %}
    {% set array_checked_values_2 = array_checked_values_2|merge([val|trim]) %}
{% endfor %}

Then, both A and B above return true.